VHF: Range, Sensing, and Communication Applications

• VHF is the 30–300 MHz radio band characterized by its use in lightning mapping, aerial links, atomic sensing, and versatile diagnostic roles.
• Research highlights VHF’s electromagnetic behavior, including geometry-dependent propagation and large Fresnel zones that impact signal range and loss.
• Advanced methodologies such as resonant cavity analysis, Rydberg atom spectroscopy, and magnon-polariton sensors expand VHF applications beyond traditional RF communication.

In contemporary technical usage, VHF most commonly denotes the very high frequency radio band, conventionally $30\text{–}300~\mathrm{MHz}$ (Rotunno et al., 2022). In the cited literature, that designation covers lightning interferometry in $40\text{–}80~\mathrm{MHz}$ (Alammari et al., 2020), maritime and UAV links at $160.4~\mathrm{MHz}$ (Galkin et al., 2023), aeronautical communications in $117.975\text{–}137~\mathrm{MHz}$ (Jamal et al., 2020), spacecraft alert downlinks in $137\text{–}138~\mathrm{MHz}$ (Cordier et al., 27 Apr 2026), and resonant atomic sensing from $240~\mathrm{MHz}$ to $900~\mathrm{MHz}$, explicitly spanning VHF into UHF (Brown et al., 2022). The same acronym, however, also appears outside RF engineering; in molten-salt dynamics it denotes the Van Hove correlation function (Banerjee et al., 2023).

1. Terminology and spectral scope

Standard RF usage places VHF between $30$ and $300~\mathrm{MHz}$ (Rotunno et al., 2022). Within that range, the literature concentrates on several practically important subbands: $117.975\text{–}137~\mathrm{MHz}$ for aeronautical VHF data links (Jamal et al., 2020), $40\text{–}80~\mathrm{MHz}$0 for the SVOM alert network (Cordier et al., 27 Apr 2026), $40\text{–}80~\mathrm{MHz}$1 for air-to-ground UAV relay measurements (Galkin et al., 2023), and $40\text{–}80~\mathrm{MHz}$2 and $40\text{–}80~\mathrm{MHz}$3 for AIS maritime signaling (Prajapati et al., 2023). In atmospheric radio work, one broadband VHF interferometer was explicitly band-limited to $40\text{–}80~\mathrm{MHz}$4 with center frequency near $40\text{–}80~\mathrm{MHz}$5 (Alammari et al., 2020).

The term is also used at the edges of the formal band. A Rydberg-atom receiver study demonstrated resonant sensing from $40\text{–}80~\mathrm{MHz}$6 to $40\text{–}80~\mathrm{MHz}$7 and described that interval as VHF to UHF (Brown et al., 2022). A cryostatic NQR spectrometer covered $40\text{–}80~\mathrm{MHz}$8 and experimentally scanned $40\text{–}80~\mathrm{MHz}$9, so part of its operating range lies below the usual $160.4~\mathrm{MHz}$0 VHF boundary (Scharfetter et al., 2018). A plausible implication is that, in practice, authors often prioritize the instrument’s target application over strict band-edge taxonomy.

Some papers also use the label more loosely than strict radio nomenclature would allow. A GEANT4-based study of RREA radio emission stated that the predicted signal lies almost entirely within $160.4~\mathrm{MHz}$1 and peaks at $160.4~\mathrm{MHz}$2, while explicitly noting that $160.4~\mathrm{MHz}$3 is not VHF in standard radio-band terminology (Khamitov et al., 2020). This suggests that, for precise interpretation, the explicit numerical frequency interval is often more informative than the acronym alone.

2. Electromagnetic behavior, resonant structures, and hardware at VHF

At VHF, geometry strongly controls propagation. In UAV relay measurements at $160.4~\mathrm{MHz}$4, a receiver at 500 m altitude measured successful reception from over 50 kilometers away, with a maximum observed range of almost 55 km; the measured air-to-ground pathloss exponent was $160.4~\mathrm{MHz}$5, compared with $160.4~\mathrm{MHz}$6 for the ground-only baseline (Galkin et al., 2023). The same study emphasized that even with aerial line of sight, the Fresnel zone remains very large at VHF and can exceed a hundred meters at long ranges, so obstacle interaction and multipath remain important.

VHF behavior is equally sensitive to enclosing structures. In the VEGA-3 vacuum chamber, the observed EMP spectrum was interpreted with the rectangular-cavity relation

$160.4~\mathrm{MHz}$7

with low-order resonances between about $160.4~\mathrm{MHz}$8 and $160.4~\mathrm{MHz}$9 (Ehret et al., 2022). The dominant measured modes included $117.975\text{–}137~\mathrm{MHz}$0, $117.975\text{–}137~\mathrm{MHz}$1, and $117.975\text{–}137~\mathrm{MHz}$2, while additional peaks in $117.975\text{–}137~\mathrm{MHz}$3 were attributed to quarter-wave resonances of internal metallic mounts (Ehret et al., 2022). The same work showed that inserting a LiF electron catcher 1 cm behind the target reduced or removed several of these low-order VHF modes by modifying the source current distribution rather than by passive RF absorption (Ehret et al., 2022).

VHF also appears as an accelerator RF technology. A high-brightness ERL-FEL injector was designed around a 216.667 MHz VHF electron gun for 100 pC bunches, with the beam accelerated to about 10 MeV, projected emittance below 0.6 mm·mrad, and peak current above 18 A (Chen et al., 2024). In a separate experimental study of 216.667 MHz CW VHF guns, an over-inserted cathode plug reduced dark current by more than two orders of magnitude in two different guns while preserving acceptable beam dynamics (Wang et al., 2024). VHF hardware is therefore not limited to communication and sensing; it also serves as an operating band for high-field normal-conducting RF structures.

A more localized use of VHF appears in biomedical inverse imaging. A 100 MHz flexible thin-wire antenna was used as a microtransmitter, and the spatial magnetic-field distribution on a sensor panel was inverted to reconstruct the antenna geometry representing a biological microstructure (Ala et al., 2013). The reported simulations used source currents from 0.1 mA to 50 mA and achieved very small relative reconstruction errors for both flat and semi-cylindrical sensor panels (Ala et al., 2013).

3. Atomic, magnonic, and spectroscopic sensing in the VHF band

One major contemporary use of VHF is atom-based electrometry. A resonant Rydberg-atom receiver demonstrated calibrated electric-field sensing from $117.975\text{–}137~\mathrm{MHz}$4 to $117.975\text{–}137~\mathrm{MHz}$5 using $117.975\text{–}137~\mathrm{MHz}$6Rb high-angular-momentum transitions $117.975\text{–}137~\mathrm{MHz}$7, accessed through three-photon all-infrared EIT (Brown et al., 2022). The study reported good agreement with quantum-defect calculations for $117.975\text{–}137~\mathrm{MHz}$8 to $117.975\text{–}137~\mathrm{MHz}$9 and measured a super-heterodyne noise floor of $137\text{–}138~\mathrm{MHz}$0 at $137\text{–}138~\mathrm{MHz}$1 (Brown et al., 2022). The central physical point was that high-$137\text{–}138~\mathrm{MHz}$2 $137\text{–}138~\mathrm{MHz}$3 transitions reduce the resonant carrier frequency by more than an order of magnitude at fixed $137\text{–}138~\mathrm{MHz}$4, enabling resonant VHF/UHF operation without pushing to extremely high principal quantum numbers (Brown et al., 2022).

A complementary Rydberg approach targeted AIS carriers near $137\text{–}138~\mathrm{MHz}$5. The HAMMER method—High Angular Momentum Matching Excited Raman—used a dressing field to couple a laser-accessed $137\text{–}138~\mathrm{MHz}$6 state into a higher-angular-momentum $137\text{–}138~\mathrm{MHz}$7 manifold and thereby enhance VHF response relative to a plain AC Stark readout (Prajapati et al., 2023). In rubidium, the best implementation achieved an equivalent single-tone sensitivity of $137\text{–}138~\mathrm{MHz}$8; at the 10% packet success threshold, the required field was $137\text{–}138~\mathrm{MHz}$9 for Rb HAMMER versus $240~\mathrm{MHz}$0 for Rb AC Stark (Prajapati et al., 2023). The same study emphasized that current technology still yields an AIS reception range approaching only $240~\mathrm{MHz}$1 for a 12.5 W Class A transmitter, but also reported about 40 dB enhancement using a split-ring resonator (Prajapati et al., 2023).

Below conventional resonant microwave sensing, Rydberg spectroscopy has also been extended to HF/VHF through Townes–Merritt / Floquet sidebands plus a GHz dressing field (Rotunno et al., 2022). In that scheme, a low-frequency field in $240~\mathrm{MHz}$2 periodically Stark-modulates a Rydberg level, creating Floquet sidebands; a second resonant field then produces an avoided crossing whose optical gap can be used to infer the HF/VHF field amplitude (Rotunno et al., 2022). The paper explicitly described this as supporting AM reception and multi-tone operation, effectively creating a Rydberg spectrum analyzer over the VHF range (Rotunno et al., 2022).

Beyond atomic sensors, a magnon-polariton magnetic probe used strong coupling between a 2 mm YIG sphere and a copper cavity to realize resonant heterodyne detection in the VHF band (Soares et al., 31 Oct 2025). By tuning the hybrid-mode splitting, the instrument operated over approximately $240~\mathrm{MHz}$3, reached sub-pT sensitivity across most of that band, achieved a best room-temperature sensitivity of $240~\mathrm{MHz}$4 at 5 mW absorbed pump power, and had estimated dynamic range above 100 dB (Soares et al., 31 Oct 2025). Because the sensed field is localized to the YIG sphere and only the component parallel to the bias field contributes, the measurement is both localized and directional (Soares et al., 31 Oct 2025).

Wideband spectroscopy in the VHF regime is not restricted to field sensors. A cryostatic zero-field NQR spectrometer used electronically tuned probeheads spanning $240~\mathrm{MHz}$5 and an interleaved subspectrum sampling strategy to scan triphenylbismuth from $240~\mathrm{MHz}$6 to $240~\mathrm{MHz}$7 at room temperature and in liquid nitrogen (Scharfetter et al., 2018). For the lowest triphenylbismuth transition, which had $240~\mathrm{MHz}$8 at low temperature, the new method provided an acceleration factor of more than 100 relative to classical stepped scanning (Scharfetter et al., 2018).

4. Communication, alerting, and operational dialogue

In terrestrial communication experiments, VHF remains a long-range operational band. A UAV relay study at $240~\mathrm{MHz}$9 used 5 W Motorola VHF handsets and a receiver carried by a DJI Matrice 200 at 500 m altitude; the measured signals remained detectable to almost 55 km, substantially outperforming the ground-only baseline (Galkin et al., 2023). The same work emphasized that the aerial channel, while closer to free space than the terrestrial case, still suffered from blockage and multipath because of the large VHF Fresnel zone (Galkin et al., 2023).

Aeronautical VHF remains an active physical-layer design space. In the band $900~\mathrm{MHz}$0, legacy VDL mode 2/3 uses D8PSK with 10.5 ksps in a 25 kHz channel, giving 31.5 kbps gross rate and about 30.75 kbps after Reed–Solomon $900~\mathrm{MHz}$1 coding (Jamal et al., 2020). Proposed Advanced VDL (A-VDL) schemes evaluate higher-order APSK, LDPC coding, alternative pulse shaping, and DFT-s-OFDM / SC-FDMA generation, with the explicit goal of increasing spectral efficiency while controlling link margin and PAPR (Jamal et al., 2020).

Space-mission operations provide a distinct VHF use case. The SVOM alert system uses $900~\mathrm{MHz}$2, 4-CPFSK modulation, 600 bit/s, and a global receiver network that had 53 stations as of 2025-11-07 (Cordier et al., 27 Apr 2026). The measured network provided 93% orbital coverage; for alert packets in September 2025, the VHF network alone achieved 25% delivery in less than 5.3 s, 50% in less than 8.9 s, and 95% completion after onboard repetition, while VHF + BeiDou duplication yielded 100% completion (Cordier et al., 27 Apr 2026). On the science-processing side, VT-VHF products from SVOM are processed on the ground through three successive pipelines, with mean runtimes of $900~\mathrm{MHz}$3 s for pre-processing, $900~\mathrm{MHz}$4 s for VVPP, and $900~\mathrm{MHz}$5 s for VTAC, for a total mean ground processing time of $900~\mathrm{MHz}$6 s (Wu et al., 27 Apr 2026).

Operational VHF traffic has also become a machine-learning corpus. VHF-Dial was introduced as the first public dataset of real-world maritime VHF communications for dialogue topic segmentation, and the DASH-DTS framework used handshake recognition, dialogue-aware similarity retrieval, and selective positive/negative sample generation to segment public-channel conversations (Sun et al., 17 Dec 2025). On VHF-Dial, the reported performance of the full system was $900~\mathrm{MHz}$7 and $900~\mathrm{MHz}$8 (Sun et al., 17 Dec 2025).

5. Atmospheric, lightning, and ionospheric diagnostics

VHF is a primary observational band for lightning mapping. A broadband interferometer study used a $900~\mathrm{MHz}$9 front-end and a crossed-baseline array with 15 m baselines to estimate azimuth and elevation of lightning sources (Alammari et al., 2020). The best-performing processing chain combined wavelet denoising with cross-correlation in the wavelet domain (CCWD) and achieved a minimum angular error of $30$0 (Alammari et al., 2020).

A broader lightning-physics perspective argues that VHF radiation is a key tracer of in-cloud electrical activity because negative leaders emit copious amounts of VHF radiation, whereas positive leaders are usually VHF quiet and return strokes radiate mainly below about $30$1 (Hare et al., 1 Jul 2026). That work emphasized unresolved mechanisms of VHF production, contrasting exponential streamer growth, streamer collision or merging, and stochastic photo-ionization fluctuations, and proposed SKA-LOW as a broadband, high-sensitivity VHF instrument for testing those models (Hare et al., 1 Jul 2026).

LOFAR has already shown that compact VHF sources can be localized on moving aircraft. In one serendipitous event, VHF pulses in $30$2 from a Boeing 777-300ER flying through high cloud were localized to the two engines and a specific spot on the tail, with improved processing giving strong-pulse location precision better than 50 cm and polarization-direction accuracy within $30$3 (Scholten et al., 20 Sep 2025). The same study explicitly stated that no emissions were detected from electrostatic wicks (Scholten et al., 20 Sep 2025).

The ionosphere is another major VHF diagnostic target. Using the VLA VHF system on Cygnus A, differential TEC between antennas was measured with precision of $30$4 (Helmboldt et al., 2012). The phase response used in that work scales as

$30$5

making low-frequency interferometers highly sensitive to electron-content fluctuations (Helmboldt et al., 2012). The same data supported both array-scale TEC-gradient reconstruction and small-scale gradient fluctuations on kilometer scales (Helmboldt et al., 2012).

6. Cross-domain meanings and conceptual limits

Outside RF engineering, VHF can denote the Van Hove correlation function. In molten $30$6, the total neutron-weighted VHF was decomposed into partial Mg–Cl, Mg–Mg, and Cl–Cl contributions using ab initio molecular dynamics, revealing that the slowest decorrelation is the oppositely charged Mg$30$7–Cl$30$8 correlation (Banerjee et al., 2023). In that literature, VHF is a real-space, time-resolved correlation function rather than a radio-frequency band, and its notation is explicitly mathematical: $30$9 (Banerjee et al., 2023)

The acronym can also drift semantically even within radio science. The RREA study cited above labeled its subject as “VHF” while reporting that the strongest runaway-electron emission lies at $300~\mathrm{MHz}$0 and is below atmospheric background noise (Khamitov et al., 2020). A plausible implication is that acronym expansion alone is insufficient for technical interpretation: in advanced literature, one must read VHF together with the stated frequency interval, physical observable, and system context.

Taken together, the cited work presents VHF as a broad technical regime rather than a single discipline. It is a communications band, a sensing band, a cavity- and structure-sensitive electromagnetic regime, a lightning and ionosphere diagnostic window, an accelerator RF technology, and, in other fields, an unrelated correlation-function acronym. The unifying requirement is precision about context: band limits, carrier frequency, observable, and architecture determine what “VHF” means in practice.